Abdallah’s far-flung Internet identity-theft and credit-card fraud, involving 217 of Forbes magazine’s list of richest people, included phony holding companies that mask his ownership of at least four buildings in Brooklyn, sources close to the case say.

Investigative sources believe that, in Brooklyn alone, Abdallah owns two brownstones on Henry Street and buildings on 14th and 18th avenues. He also has “virtual bank accounts,” investigators say, jammed with millions.

Abdallah is suspected of opening bank accounts in the Caribbean and as far away as Australia under the “cloned” identities of his victims and he may have hidden other millions of dollars looted from their brokerage and investment-bank accounts.

Many were stunned to learn that their private financial lives were compromised and cloned, allegedly by Abdallah’s use of high-tech computers, cell phones and fax machines.

Police Commissioner Bernard Kerik said yesterday that when Abdallah had to make verbal contact, he was soft-spoken and charming, helping convince officials at credit-reporting companies and brokerage houses that he was legitimate.

Police say he used computers at public libraries and Web-enabled cellular phones to carry out what officials believe is the single largest Internet identity theft ever.

They say Abdallah, who continued to do menial work at a Brooklyn restaurant, allegedly obtained around $1 million on some 400 stolen credit cards.

The crime spree surfaced when he allegedly tried to transfer as much as $10 million from an account belonging to Thomas Siebel, founder of Siebel Systems, to a new account he set up.

Police say it could take months for the cops, brokerage houses and victims to electronically track the accounts and determine if other millions have been stolen.

Kerik described Abdallah as “very innovative, very creative.”

He even appeared once as an “expert” on a training video on credit-card fraud prevention as part of his sentence for an earlier conviction, sources said.

Kerik said Abdallah had a long arrest record, including 11 collars by city cops and another 14 by the feds, primarily for credit-card and bank fraud. He is being held on $1 million bail.

Abdallah’s lawyer, Sam Gregory, said his client is innocent and that prosecutors have “made an unfair leap” from possession of a dog-eared Forbes “Richest People” edition to stealing their money.

Meanwhile, the relative who employed Abdallah as a dishwasher at his Brooklyn restaurant said he thought the swindler had turned over a new leaf.

“He was a smart, intelligent person, was punctual, worked about 30 hours a week, said Faried Assad, who owns Zaytoon’s, a Middle Eastern restaurant in Carroll Gardens. “I thought he was totally rehabilitated. We would often sit down, and I was curious about his life and being in jail, and he would say if he could do everything again, he would not commit another crime.

“He’d say how he wasted his youth and took his family’s dignity and reputation down.”